Share artifact declaration validation

internal/artifact/artifact.go

@@ -90,3 +90,30 @@ func ExpectedBuild(binaryName, version string, targets []Target) []Declaration {
 	}
 	return declarations
 }
+
+// ValidateDeclarations matches recorded artifact identities to selected targets.
+func ValidateDeclarations(binaryName, version string, targets []Target, recorded []Declaration) error {
+	if len(recorded) != len(targets) {
+		return fmt.Errorf("artifact and target counts do not match")
+	}
+	want := make(map[Target]string, len(targets))
+	for _, declaration := range ExpectedBuild(binaryName, version, targets) {
+		target := declaration.Target
+		if !ValidComponent(target.OS) || !ValidComponent(target.Arch) {
+			return fmt.Errorf("invalid target %q/%q", target.OS, target.Arch)
+		}
+		if _, exists := want[target]; exists {
+			return fmt.Errorf("repeats target %q/%q", target.OS, target.Arch)
+		}
+		want[target] = declaration.Filename
+	}
+	seen := make(map[Target]bool, len(recorded))
+	for _, declaration := range recorded {
+		name, ok := want[declaration.Target]
+		if !ok || seen[declaration.Target] || declaration.Filename != name {
+			return fmt.Errorf("artifact %q does not match a selected target and its declared name", declaration.Filename)
+		}
+		seen[declaration.Target] = true
+	}
+	return nil
+}